Tuning the pinning direction of giant magnetoresistive sensor by post annealing process

The Internet of Things has created an increasing demand for giant magnetoresistive (GMR) sensor owing to its high sensitivity, low power-consumption and small size. A full Wheatstone bridge GMR sensor is fabricated on 6-inch wafers with an annealing process on patterned devices. It can be observed that GMR resistors could have different pinning directions in one wafer by magnetic resistance measurements and MATLAB simulations. The full Wheatstone bridge device shows a sensitivity of 2 mV/V/mT in a linear range of ±6 mT, and its angular response to the surrounding magnetic field is as low as 0.08 mT. These results demonstrate a new approach to high-sensitive and low-cost GMR sensors with a controllable post annealing process.